Various machines such as printers, scanners and faxing machines are common peripheral devices of a computer system. These machines are usually equipped with automatic document feeders.
FIG. 1A is a schematic cross-sectional view illustrating a conventional automatic document feeding and scanning apparatus. As shown in FIG. 1A, the scanning apparatus 1 comprises an automatic document feeder 1a and a scanner mechanism 1b. The automatic document feeder 1a is installed in an upper cover 2. The automatic document feeder 1a has an outlet 14. The use of the automatic document feeder 1a may successively feed a stack of sheet-like articles and eject the sheet-like articles out of the outlet 14.
The scanner mechanism 1b comprises a scanner casing 10, a transparent platform 11, a glass plate 12, a frame 13 and a scanning module 3. The scanner casing 10 is disposed under the automatic document feeder 1a. The scanning module 3 is disposed within the scanner casing 10.
The transparent platform 11 and the glass plate 12 are fixed in the scanner casing 10. In a case that a flatbed scanning operation is performed, the flatbed-scanning document to be scanned is supported on the transparent platform 11. The light beams emitted from the scanning module 3 are transmissible through the glass plate 12. As such, in a case that a sheetfed scanning operation is performed, the scanning module 3 may scan the sheetfed-scanning document through the glass plate 12.
FIG. 1B is an enlarged fragmentary view of FIG. 1A. The frame 13 is arranged between the transparent platform 11 and the glass plate 12. The frame 13 comprises a protrusion 13a and a vertical wall 13b. The protrusion 13a is used for supporting the glass plate 12 such that the glass plate 12 is coupled with the vertical wall 13b. By the frame 13, the transparent platform 11 and the glass plate 12 are fixed on the scanner casing 10. In addition, the frame 13 may facilitate guiding the sheetfed-scanning document to the outlet 14.
The structure for fixing the sheetfed-scanning glass plate 12, however, still has some drawbacks. Generally, the frame 13 for fixing the glass plate 12 is made of plastic material. If the frame 13 is subject to plastic deformation, the protrusion 13a may be shifted downwardly. Once the scanning module 3 is moved under the glass plate 12, the protrusion 13a is possibly hit by the moving scanning module 3. In this circumstance, the scanning module 3 fails to successfully move to the region under the transparent platform 11 to perform the scanning operation. If the protrusion 13a is removed and the glass plate 12 is directly bonded to the vertical wall 13b of the frame 13, the problem of hitting the protrusion 13a by the moving scanning module 3 could be eliminated. However, since the glass plate 12 is no longer supported by the protrusion 13a, the glass plate 12 is possibly detached from the frame 13 if the scanning apparatus has been used for a long term. In this circumstance, the use life of the automatic document feeding and scanning apparatus is shortened.